1. Field of the Invention
The present invention relates to a process for the selective concentration of uranium from sea water through chemical accumulation onto a solid adsorption medium, which does not necessitate any H.sup.+ ions for regeneration, in particular onto titanium oxide hydrate and subsequent elution with a carbonate-containing eluent.
The concentration of uranium from sea water through the accumulation onto adsorption media such as titanium oxide hydrate or ion exchanger is not absolutely specific, in essence, there are also accumulated other cations which are present in the sea. Hereby, disruptive above all are the bivalent calcium and magnesium ions whose mole concentrations in seawater are higher by a factor of greater than 10.sup.5 relative to that of the uranium. Notwithstanding the significantly higher receiving tendency for uranium by the adsorption medium, there must be taken into account a quantitatively predominent accumulation of the above mentioned competitive ions on the titanium oxide hydrate, which will accumulate for example, from seawater, substantially more calcium and magnesium than uranium.
2. Discussion of the Prior Art
During the chemical separation of the accumulated heavy-metal ions and the regeneration of the adsorption medium, in the usual manner there are also again separated the accumulated ballast ions (in essence, particularly CA.sup.++ ad Mg.sup.++). Relative to the uranium, in which there alone is interest in the raw material recovery thereof, this is interconnected with a relatively high use of chemicals. This is valid, for example, for the elutriation of uranium-charged titanium oxide hydrate with 1M aqueous ammonium carbonate solution. During this process, in addition to the accumulated uranium, calcium and magnesium are almost completely elutriated by the adsorption medium. Independently of the already mentioned high use of chemicals, this has the additional disadvantage that calcium and magnesium are hereby precipitated as carbonate on the adsorption medium and thereby may possibly obstruct the adsorber surface to subsequent accumulating processes.